So in the midst of my 3800SC sitting on a stand outside... I was doing all necessary swap work for it to go into my '88 Fiero.
I swapped this motor in 2 days before the snow fell, thankfully. Otherwise it'd be outside under the white stuff, but I forgot one thing... What should I do to the timing cover heater hose port? I'm sticking Alt in stock location, I haven't done anything to the Timing cover hole, Can I run it through that bracket to a heater core line or?....
I had the LIM tapped to accept a 5/8th barbed nipple, (May need to replace LIM due to coolant sensor threads coming out)
Where can I route this to now? I'd rather not take the timing cover off, too far past that point for me specifically.
I wouldn't trust myself to tap 3/4" NPT to my timing cover, and I also do not feel the need to take my timing cover off. Since my motor and trans is already sitting in the car.
Plugging the hole is the way to go. I used a rubber compression plug at first and it blew out of the hole on a hot summer day about a year after I finished the install. No warning. So then I put threads in it and jb welded the npt plug so it would never happen again.
If you are mounting the alternator in the stock 3800 location, then I have to assume you are using the stock 3800 alternator bracket. This bracket has both heater lines going thru it. Since you said you have an 88, you're only going to use the one passage that connects to the lower intake manifold (to connect to your heater core hose in the engine compartment). The other heater hose port can be plugged or used as a fill point.
As others have said, rubber plugs tend to fail so it is best to use a screw-on plug. You can pull the alternator mounting bracket off the 3800 and tap threads into it for such a plug then reinstall (you don't have to remove the timing cover).
Or, you can pull the steel hose nipple insert out of the aluminum alternator bracket and tap threads into the steel insert for a plug, then reinstall it - all of which can be done without even pulling the alternator bracket. I do recommend replacing the o-rings on the steel nipple once you remove it if the stock o-ring(s) that are already on the nipple need to be replaced.
What about JB welding a freeze plug in as seen in automarshal's thread. Then no need to tap. That's what I did, I can't say how it holds up because my engine is still on the stand awaiting the warmer weather to be put in.
------------------ ===Always trying to find time to work on cars=== Louis Duet Baldwin, Long Island, NY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "Blue" <= '85 Fiero GT Stock V6---Stock everything. Trying to keep it 'mostly' that way. But I just got the 3800sc to swap into it! ~~~~~~~~~~~~~~~~~~~~~ "Boo" <= '81 Delorean DMC-12 VIN #5835 Stock PRV engine Peugot 604 Intake manifold Exhaust headers Anti-3rd brake light
[This message has been edited by Lou and Blue (edited 03-04-2015).]
What about JB welding a freeze plug in as seen in automarshal's thread. Then no need to tap. That's what I did, I can't say how it holds up because my engine is still on the stand awaiting the warmer weather to be put in.
I'm not crazy about JB Weld. Not saying that it won't work but I just wouldn't want to rely on it not leaving me stranded on the side of the highway should it ever decide to fail and let that plug blow out.
87FieroSport has an 88 model with only one heater hose to worry about when doing a 3800SC swap. The LIM is the feed to the heater core. It sounds like he has tapped that hole with a 3/4" NPT tap and has fitted it with a 5/8" barb for his heater core feed. With lots of excitement, he has installed his engine without doing anything with the open coolant hole in the timing cover. This hole in the timing cover is 1" (not 3/4"). Some have tried to tap threads into it and plug it but there is little to no quality threads that can be made making this way some what difficult and untrustworthy. A rubber expansion plug is also not a very good idea and will definitely fail/ blow out. Using a freeze plug aka frost plug aka expansion plug has proven to work well. Again it is a one inch steel expansion/frost plug. Dorman part #555-017. I paid $.41 for it. The JB weld is not required but I used it as 10 cent insurance. This plug is just like the plugs in the side of engine blocks...... can they fail? yes. Mine so far has not failed. Is this a difficult task to hammer in a plug with the engine already installed??? IDK.... never tried. I'm sure its a tight fit but worth the try. Use a socket that fits into the plug and bang it in flush.
The 3/4" pipe tap will cut threads into the hole. jB Weld and a threaded plug will seal the opening with no issues. I have done it several times. Good luck putting in a freeze plug without lowering the cradle......
I want to clarify what I meant by not being crazy about JB Weld. What I meant by that is if you are trying to seal a loose fitting plug into an opening using JB Weld, I wouldn't trust it.
However, if you are talking about sealing threads with JB Weld or basically gluing a "press fit" freeze plug into a hole using JB Weld; then that's totally acceptable. That is, if you basically never want to remove that plug ever again. I just wouldn't trust it with a loose fitting plug - that's all.
I wish it was for lots of excitement. More so the fact that we now have 5 feet of snow, and otherwise my motor would be under all of it. So time was a factor.
I do plan on the stock location for the alt, but isn't there a passage in the alt bracket that connects both coolant passages? If I'm hearing some correctly:
- Use LIM fitting that I have tapped and accepted a 5/8 barbed fitting for heater core. - Use aluminum replacement "L" tube for the timing cover, and use that passage as a "fill" point for coolant, cap the one that used to feed to the LIM.
No. Use the LIM 5/8 barb to feed the heater core. Heater core return to the passenger side coolant tube. Tap and plug the port on the timing cover.
The alternator bracket will be dry. Initial coolant fill through the thermostat housing port, then install thermostat and housing. There is no need for a dedicated fill port in the engine compartment.
The factory 3800 alternator bracket contained a bypass for the cooling system (a small passage was drilled between the two heater core passages that pass thru the alternator bracket). This "bypass" is meant to prevent the water pump from "dead-heading" in the event the heater core or lines become restricted at the time the thermostat is closed. Every GM engine that utilized a thermostat mounted on the coolant outlet port of the engine has some sort of a coolant bypass. Some, like on the Gen1 SBC V8 engines are integral to the water pump and block. Others, like the 3800, are external to the block. Newer design engines that have the t-stat mounted on the coolant inlet port on the engine don't need a bypass since water flow to the pump is cut off by a closed thermostat, so no excessive head pressure can build.
Anyway, getting back to a Fiero 3800 swap; as long as your heater core and lines aren't restricted, you should be "ok" running without this bypass in the system. But if something happens and a heater core line under the car gets crushed or the heater core becomes restricted, it is possible that without this bypass you could have a gasket in the engine or an external hose (or even the heater core itself) blow out due to excessive water pump head pressure buildup.
Got my freeze plug, put it in. I have a lot of the motor disassembled still so it was easy to get in there.
On a side note:
The '88 I bought, had a 3800 Series 1 NA installed, drove it for a daily, the 3800 supercharged is now in it. - The exhaust he used has the flex-flange from the 3800SC, he just drilled two holes closer to use the 3800NA manfiold.
So I got my exhaust system out of it, and a good deal.
I'm not ready to pull the swapped engine out of my 85 yet. (another story). When I put it in the 85, I had very limited time. Had a series 1 SC that spun a bearing(another story) and quickly had to swap in a series II SC. So I don't have picks yet. When I did the swap. I used one of the (steel) inserts that go into the top of the alternator/power steering bracket. The ones that the heater hoses go to in the 3800 stock location. They are about an inch deep with a o-ring groove, with a fitting for a hose. They have a flat bracket that a bolt holds them to the alternator bracket. They are slightly larger than the hole in the timing cover. So I carefully filed and sanded it to fit into the hole. Then I bent and drilled the hole on the bracket so it could use one of the timing cover bolts to hold it in. I then cut off the hose fitting and tapped it so I could put an elbow and a hose barb, so it wouldn't have to come through the belt routing. But I am using a low alternator location. And not using the stock 3800 brackets. I also raided a Saturn Ion coolant bottle. Colbalt/Cavalier with Ecotech 2.2 is the same. It has a heater sized hose on the bottom and a small hose towards the top. When I raided the bottle I also took the fitting for the small hose that went into the head. Where the stock 3800 bleeder is in the thermostat housing, I tapped that to receive the small hose fitting. Then T'ed the larger hose to the fitting in the timing cover and heater hose. For 88 no Tee, just bottle to timing cover fitting. That also kept me from having to fab a thermostat housing. Right now the 85 doesn't have cruise. The bottle is mounted in that corner. I'll have to move the cruise in the 87 when I do the swap. But I most likely will be converting it to digital cruise and have more room. When I fill it I remove the radiator cap. Fill till the radiator fills. Reinstall the front cap. Start the engine, fill. Wait for thermostat to open and fill the rest of the way. When I get the other swap ready, I'll try to make it as plug and play as possible and do a better job on the wiring and exhaust. The rest is pretty much as I need it.
[This message has been edited by cmechmann (edited 03-14-2015).]